network related lockdep splat in 3.0-rc6+
Subsystems (2)
This has some additional NFS patches as well, but is otherwise un-tainted.
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[ INFO: possible circular locking dependency detected ]
3.0.0-rc6+ #13
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gnuserver/2266 is trying to acquire lock:
(rcu_node_level_0){..-...}, at: [<ffffffff810a7439>] rcu_report_unblock_qs_rnp+0x52/0x72
but task is already holding lock:
(&rq->lock){-.-.-.}, at: [<ffffffff81045da5>] sched_ttwu_pending+0x34/0x58
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&rq->lock){-.-.-.}:
[<ffffffff8107b4d5>] lock_acquire+0xf4/0x14b
[<ffffffff8147e451>] _raw_spin_lock+0x36/0x45
[<ffffffff8103da13>] __task_rq_lock+0x5b/0x89
[<ffffffff81046ab6>] wake_up_new_task+0x41/0x116
[<ffffffff810496d5>] do_fork+0x207/0x2f1
[<ffffffff81010d25>] kernel_thread+0x70/0x72
[<ffffffff8146598d>] rest_init+0x21/0xd7
[<ffffffff81aa9c76>] start_kernel+0x3bd/0x3c8
[<ffffffff81aa92cd>] x86_64_start_reservations+0xb8/0xbc
[<ffffffff81aa93d2>] x86_64_start_kernel+0x101/0x110-> #2 (&p->pi_lock){-.-.-.}:
[<ffffffff8107b4d5>] lock_acquire+0xf4/0x14b
[<ffffffff8147e565>] _raw_spin_lock_irqsave+0x4e/0x60
[<ffffffff810468d0>] try_to_wake_up+0x29/0x1a0
[<ffffffff81046a54>] default_wake_function+0xd/0xf
[<ffffffff8106751a>] autoremove_wake_function+0x13/0x38
[<ffffffff810395d0>] __wake_up_common+0x49/0x7f
[<ffffffff8103c79a>] __wake_up+0x34/0x48
[<ffffffff810a74a9>] rcu_report_exp_rnp+0x50/0x89
[<ffffffff810a8032>] __rcu_read_unlock+0x1e9/0x24e
[<ffffffff8111a41e>] rcu_read_unlock+0x21/0x23
[<ffffffff8111a556>] fget_light+0xa2/0xac
[<ffffffff81128bc1>] do_sys_poll+0x1ff/0x3e5
[<ffffffff81128f3b>] sys_poll+0x50/0xba
[<ffffffff81484d52>] system_call_fastpath+0x16/0x1b-> #1 (sync_rcu_preempt_exp_wq.lock){......}:
[<ffffffff8107b4d5>] lock_acquire+0xf4/0x14b
[<ffffffff8147e565>] _raw_spin_lock_irqsave+0x4e/0x60
[<ffffffff8103c783>] __wake_up+0x1d/0x48
[<ffffffff810a74a9>] rcu_report_exp_rnp+0x50/0x89
[<ffffffff810a8c2c>] sync_rcu_preempt_exp_init.clone.0+0x3e/0x53
[<ffffffff810a8d1c>] synchronize_rcu_expedited+0xdb/0x1c3
[<ffffffff813c0db3>] synchronize_net+0x25/0x2e
[<ffffffff813c3382>] rollback_registered_many+0xee/0x1e1
[<ffffffff813c3489>] unregister_netdevice_many+0x14/0x55
[<ffffffff813c361b>] default_device_exit_batch+0x98/0xb4
[<ffffffff813bd95e>] ops_exit_list+0x46/0x4e
[<ffffffff813bde8c>] cleanup_net+0xeb/0x17d
[<ffffffff81061343>] process_one_work+0x230/0x41d
[<ffffffff8106379f>] worker_thread+0x133/0x217
[<ffffffff81066f9c>] kthread+0x7d/0x85
[<ffffffff81485ee4>] kernel_thread_helper+0x4/0x10-> #0 (rcu_node_level_0){..-...}:
[<ffffffff8107ace2>] __lock_acquire+0xae6/0xdd5
[<ffffffff8107b4d5>] lock_acquire+0xf4/0x14b
[<ffffffff8147e451>] _raw_spin_lock+0x36/0x45
[<ffffffff810a7439>] rcu_report_unblock_qs_rnp+0x52/0x72
[<ffffffff810a7ff0>] __rcu_read_unlock+0x1a7/0x24e
[<ffffffff8103d34d>] rcu_read_unlock+0x21/0x23
[<ffffffff8103d3a2>] cpuacct_charge+0x53/0x5b
[<ffffffff81044d04>] update_curr+0x11f/0x15a
[<ffffffff81045a37>] enqueue_task_fair+0x46/0x22a
[<ffffffff8103d2c0>] enqueue_task+0x61/0x68
[<ffffffff8103d2ef>] activate_task+0x28/0x30
[<ffffffff81040b3b>] ttwu_activate+0x12/0x34
[<ffffffff81045d5f>] ttwu_do_activate.clone.4+0x2d/0x3f
[<ffffffff81045db4>] sched_ttwu_pending+0x43/0x58
[<ffffffff81045dd2>] scheduler_ipi+0x9/0xb
[<ffffffff81021e10>] smp_reschedule_interrupt+0x25/0x27
[<ffffffff81485c73>] reschedule_interrupt+0x13/0x20
[<ffffffff813fce40>] rcu_read_unlock+0x21/0x23
[<ffffffff813fd52d>] ip_queue_xmit+0x35e/0x3b1
[<ffffffff8140f5f3>] tcp_transmit_skb+0x785/0x7c3
[<ffffffff81411e23>] tcp_write_xmit+0x806/0x8f5
[<ffffffff81411f63>] __tcp_push_pending_frames+0x20/0x4d
[<ffffffff8140411f>] tcp_push+0x84/0x86
[<ffffffff81406577>] tcp_sendmsg+0x674/0x775
[<ffffffff81423d68>] inet_sendmsg+0x61/0x6a
[<ffffffff813af67a>] __sock_sendmsg_nosec+0x58/0x61
[<ffffffff813b0db5>] __sock_sendmsg+0x3d/0x48
[<ffffffff813b1631>] sock_sendmsg+0xa3/0xbc
[<ffffffff813b1bf5>] sys_sendto+0xfa/0x11f
[<ffffffff81484d52>] system_call_fastpath+0x16/0x1bother info that might help us debug this:
Chain exists of: rcu_node_level_0 --> &p->pi_lock --> &rq->lock Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&rq->lock);
lock(&p->pi_lock);
lock(&rq->lock); lock(rcu_node_level_0);
*** DEADLOCK ***
2 locks held by gnuserver/2266:
#0: (sk_lock-AF_INET){+.+.+.}, at: [<ffffffff81405f24>] tcp_sendmsg+0x21/0x775 #1: (&rq->lock){-.-.-.}, at: [<ffffffff81045da5>] sched_ttwu_pending+0x34/0x58
stack backtrace: Pid: 2266, comm: gnuserver Not tainted 3.0.0-rc6+ #13 Call Trace: <IRQ> [<ffffffff8107a13d>] print_circular_bug+0x1fe/0x20f [<ffffffff8107ace2>] __lock_acquire+0xae6/0xdd5 [<ffffffff810a7439>] ? rcu_report_unblock_qs_rnp+0x52/0x72 [<ffffffff8107b4d5>] lock_acquire+0xf4/0x14b [<ffffffff810a7439>] ? rcu_report_unblock_qs_rnp+0x52/0x72 [<ffffffff8147e451>] _raw_spin_lock+0x36/0x45 [<ffffffff810a7439>] ? rcu_report_unblock_qs_rnp+0x52/0x72 [<ffffffff8147ea3b>] ? _raw_spin_unlock+0x45/0x52 [<ffffffff810a7439>] rcu_report_unblock_qs_rnp+0x52/0x72 [<ffffffff810a7f25>] ? __rcu_read_unlock+0xdc/0x24e [<ffffffff810a7ff0>] __rcu_read_unlock+0x1a7/0x24e [<ffffffff8103d34d>] rcu_read_unlock+0x21/0x23 [<ffffffff8103d3a2>] cpuacct_charge+0x53/0x5b [<ffffffff81044d04>] update_curr+0x11f/0x15a [<ffffffff81045a37>] enqueue_task_fair+0x46/0x22a [<ffffffff8103d2c0>] enqueue_task+0x61/0x68 [<ffffffff8103d2ef>] activate_task+0x28/0x30 [<ffffffff81040b3b>] ttwu_activate+0x12/0x34 [<ffffffff81045d5f>] ttwu_do_activate.clone.4+0x2d/0x3f [<ffffffff81045db4>] sched_ttwu_pending+0x43/0x58 [<ffffffff81045dd2>] scheduler_ipi+0x9/0xb [<ffffffff81021e10>] smp_reschedule_interrupt+0x25/0x27 [<ffffffff81485c73>] reschedule_interrupt+0x13/0x20 <EOI> [<ffffffff810a7e9b>] ? __rcu_read_unlock+0x52/0x24e [<ffffffff813fce40>] rcu_read_unlock+0x21/0x23 [<ffffffff813fd52d>] ip_queue_xmit+0x35e/0x3b1 [<ffffffff813fd1cf>] ? ip_send_reply+0x247/0x247 [<ffffffff8140f5f3>] tcp_transmit_skb+0x785/0x7c3 [<ffffffff81411e23>] tcp_write_xmit+0x806/0x8f5 [<ffffffff810e646f>] ? might_fault+0x4e/0x9e [<ffffffff81403e25>] ? copy_from_user+0x2a/0x2c [<ffffffff81411f63>] __tcp_push_pending_frames+0x20/0x4d [<ffffffff8140411f>] tcp_push+0x84/0x86 [<ffffffff81406577>] tcp_sendmsg+0x674/0x775 [<ffffffff81423d68>] inet_sendmsg+0x61/0x6a [<ffffffff813af67a>] __sock_sendmsg_nosec+0x58/0x61 [<ffffffff813b0db5>] __sock_sendmsg+0x3d/0x48 [<ffffffff813b1631>] sock_sendmsg+0xa3/0xbc [<ffffffff810ea6ae>] ? handle_pte_fault+0x7fc/0x84d [<ffffffff8111a4e9>] ? fget_light+0x35/0xac [<ffffffff813b16b2>] ? sockfd_lookup_light+0x1b/0x53 [<ffffffff813b1bf5>] sys_sendto+0xfa/0x11f [<ffffffff811326ac>] ? mntput_no_expire+0x52/0x109 [<ffffffff81132784>] ? mntput+0x21/0x23 [<ffffffff8111af94>] ? fput+0x1a3/0x1b2 [<ffffffff8109f0a1>] ? audit_syscall_entry+0x119/0x145 [<ffffffff81484d52>] system_call_fastpath+0x16/0x1b
Signature · 2 lines
Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com
David Miller
maintainerFrom: Ben Greear <[email protected]>
Date: Fri, 08 Jul 2011 15:38:17 -0700
Quoted 3 lines
This has some additional NFS patches as well, but is otherwise un-tainted.
"networking related" when it's honking in the scheduler wakeup paths?